1. Field of the Invention
The present invention relates to an opening and closing assembly including an opening and closing mechanism and first and second casing bodies pivotable relative to each other, wherein the opening and closing mechanism is capable of maintaining an open position of the second casing body relative to the first casing body and opening and closing the second casing body relative to the first casing body in suitable manners.
2. Discussion of Related Art
Conventionally, there have been proposed various kinds of structures each of which is to be incorporated in an opening and closing assembly including first and second casing bodies pivotable relative to each other through a hinge and each of which is arranged to maintain an open position of the second casing body relative to the first casing body when the second casing body should be held in the open position. As an example of the opening and closing assembly incorporating such a structure, there is a so-called “multifunction device”, i.e., a device having multifunctions such as printer, scanner, copier and facsimile functions.
For performing the multifunctions, the multifunction device has an image recording unit operable to record an image on a recording medium and also an image reading unit operable to read an image carried on an original.
The image reading unit is provided by a flat bed scanner, for example. In some case, the flat bed scanner is provided with an automatic document feeder (ADF) that is arranged to automatically feed an original document. The flat bed scanner has a document setting table having an upper surface that is provided by a platen glass, and also a document cover for covering the upper surface of the document setting table and fixing the original document onto the platen glass. When an image carried on the original document is to be read by the image reading unit, the original document is set on the platen glass after the document cover is opened relative to the document setting table. The original document is fixed onto the platen glass, with the document cover is closed relative to the document setting table. The original document is scanned by an image sensor that is reciprocatably disposed inside the document setting table, i.e., below the platen glass, whereby the image carried on the original document is read based on an electric signal representative of the image.
In the multifunction device, it is common that the image reading unit is disposed on an upper side of the image recording unit, for facilitating setting of the original document onto the platen glass of the flat bed scanner.
On the other hand, the image recording unit of the multifunction device requires a maintenance work such as replacement of ink cartridges and removal of recording mediums jammed inside the image recording unit. For allowing an operator to access inside the image recording unit for carrying out the maintenance work, at least a part of a casing body of the image recording unit has to be exposed as needed.
The above-described opening and closing mechanism is employed to open and close the image reading unit relative to the image recording unit. It is preferable that the image reading unit is held open relative to the image recording unit during the maintenance work. To this purpose, as disclosed in JP-U-3093658 (Japanese Utility Model registered in 2003), the opening and closing mechanism has a stopper member that is disposed in a diagonal attitude for maintaining the open position of the image reading unit relative to the image recording unit
According to the disclosure of JP-U-3093658, the image reading unit (scanner casing body) is attached to the image recording unit (printer casing body), pivotably about a pivot axis that is provided in its end portion. Between the image reading unit and the image recording unit, the stopper member (scanner support stand) is provided to maintain a state in which the image reading unit is opened relative to the image recording unit by a predetermined angle. On a lower surface of the image reading unit, there is provided a pivot shaft receiver by which one of opposite end portions of the stopper member is pivotably received. On an upper surface of the image recording unit, there is provided an accommodating portion (scanner-support-stand accommodating hole) that is arranged to accommodate therein the stopper member such that the other of the opposite end portions of the stopper member is first introduced into the accommodating portion and then the above-described one of the opposite end portions of the stopper member is introduced into the accommodating portion. The above-described other of the opposite end portions of the stopper member includes an engaging portion that can be held in engagement with an opening of the accommodating portion and an elastic body that is elastically pressed against a periphery of the opening of the accommodating portion. With the engagement of the engaging portion of the stopper member with the opening of the accommodating portion, the image reading unit is held in its open position relative to the image recording unit. With disengagement of the engaging portion of the stopper member from the opening of the accommodating portion, the stopper member is accommodated in the accommodating portion whereby the image reading unit is placed in its closed position relative to the image recording unit. In an initial stage of a closing transition from the open position to the closed position and also a final stage of an opening transition from the closed position to the open position, the above-described elastic body is elastically pressed against the periphery of the opening of the accommodating portion whereby a load is applied against pivot motion of the image reading unit relative to the image recording unit. That is, in the initial stage of the closing transition and the final stage of the opening transition, the image reading unit is slowly pivoted. It is therefore possible to prevent a hand of an operator from being caught between the image reading unit and the image recording unit during a maintenance work, since the image reading unit is not rapidly pivoted from the above-described predetermined angle toward the closed position.
However, in the above-described arrangement disclosed in JP-U-3093658, the load can not be applied against the pivot motion in a final stage of the closing transition, i.e., in a stage until the image reading unit is completely closed relative to the image recording unit after the above-described initial stage of the closing transition. That is, in the final stage of the closing transition, the image reading unit could be rapidly pivoted toward the closed position due to its own weight, causing collision of the image reading unit with the image recording unit, and accordingly causing a risk of damages of the image reading and recording units.
JP-H01-29815Y2 (Japanese Examined Utility Model Application published in 1989) discloses an opening and closing mechanism arranged to open and close a cover body attached to a casing body that provides, for example, a data terminal unit. According to the disclosure of JP-H01-29815Y2, the cover body is pivotable relative to the casing body to which the cover body is connected via a guide member. The guide member is provided by an arcuate-shaped member that is arranged to extend from a side surface of the cover body toward the casing body. The guide member has a guide slot formed therethrough to be aligned with a position of a screw receiver hole that is provided in the casing body. A screw bolt is provided to pass through the guide slot and the screw receiver hole and to be screwed into a nut, so that the guide member and the casing body are gripped between a head of the screw bolt and the nut, for thereby maintaining a predetermined angular position in which the cover body is opened relative to the casing body by a predetermined angle. Further, in JP-H01-29815Y2, a torsion spring is provided in the casing body, so as to bias the cover body in a direction away from the casing body. In a final stage of the closing transition from the open position toward the closed position, the cover body is biased by the torsion spring in the direction away from the casing body. Therefore, in the arrangement disclosed in JP-H01-29815Y2, it is possible to prevent the cover body from being rapidly pivoted toward the closed position and accordingly to avoid the image reading and recording units from being damaged.